The Sonochemical Synthesis of Nanosized Hydroxides

Cobalt hydroxide with an interlayer spacing of 7.53 A and needle-like morphology has been synthesized with the aid of ultrasound radiation [124]. Characterization methods indicate the formation of a-cobalt hydroxide. Thermal decomposition of the hydroxide at 300 °C under air or argon yields nanometer-sized oxide particles of C03O4 (ca. 9 nm) and CoO (ca. 6 nm), respectively. 

In a different study [125], an a-cobalt hydroxide with an interlayer spacing of 12.65 A was synthesized in sheet shapes with dimensions of 100-120 nm with the 

Because of its many applications, a few attempts are known in which ultrasonic waves have been applied for the synthesis of nanosized titania. Yu and coworkers [126] discovered a novel method for preparing highly photoactive nano-sized Ti02 photocatalysts with anatase and brookite phases. The method has been developed by hydrolysis of titanium tetraisopropoxide in pure water or a 1 1 Et0H H20 solution under ultrasonic irradiation the photocatalytic activity of Ti02 particles prepared by this method exceeded that of Degussa P25. 

in a similar reaction [127], found a way to selectively prepare anatase or rutile as well as their mixtures. This was achieved by using various precursors and employing ultrasound irradiation. The products, the particle sizes of which are nanometric ( 9 nm), are dependent both upon the reaction temperature and the precursor used a substantial reduction in reaction time, as well as reaction temperature is observed, as compared to the corresponding hydrothermal processes. 

The application of ultrasound dramatically increases the rate of exfoliation of HxTi2 x/404 yH20 in the presence of aqueous tetrabutylammonium (TBA) hydroxide [130]. The effect of ultra sonication power and processing time on particle size distributions are evaluated. Applied powers of 60-300 W and reaction times of 2-30 min effectively reduce the H-Ti particle size to 100 nm. Both particle size distribution analysis and UV-Vis spectroscopy were used to study the effect of the 

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